On April 27, 2015, the Whatcom County Health Department (WCHD) in Bellingham, Washington, was notified by a local laboratory regarding three children with presumptive Escherichia coli O157 infection. WCHD interviewed the parents, who indicated that all three children had attended a dairy education event held in a barn April 20-24, 2015, during a school field trip. WCHD, the Washington State Department of Health, and CDC investigated to determine the magnitude of the outbreak, identify risk factors and potential environmental sources of infection, and develop recommendations. A total of 60 cases (25 confirmed and 35 probable) were identified, and 11 patients were hospitalized.

Beef and leafy vegetables were the most common sources of these outbreaks.

Listeria monocytogenes is a foodborne pathogen that can cause bacteraemia, meningitis, and complications during pregnancy. In July 2012, molecular subtyping identified indistinguishable L. monocytogenes isolates from six patients and two samples of different cut and repackaged cheeses. A multistate outbreak investigation was initiated. Initial analyses identified an association between eating soft cheese and outbreak-related illness (odds ratio 17.3, 95% confidence interval 2.0-825.7) but no common brand. Cheese inventory data from locations where patients bought cheese and an additional location where repackaged cheese yielded the outbreak strain were compared to identify cheeses for microbiological sampling. Intact packages of imported ricotta salata yielded the outbreak strain. Fourteen jurisdictions reported 22 cases from March-October 2012, including four deaths and a fetal loss. Six patients ultimately reported eating ricotta salata; another reported eating cheese likely cut with equipment also used for contaminated ricotta salata, and nine more reported eating other cheeses that might also have been cross-contaminated. An FDA import alert and US and international recalls followed. Epidemiology-directed microbiological testing of suspect cheeses helped identify the outbreak source. Cross-contamination of cheese highlights the importance of using validated disinfectant protocols and routine cleaning and sanitizing after cutting each block or wheel.

Shigella with decreased susceptibility to azithromycin (DSA-Shigella) is emerging in the United States.1 This is concerning because azithromycin is recommended for treatment of multidrug-resistant shigellosis among children and adults.2 In the United States, Shigella causes approximately 500,000 illnesses annually, mainly in children <10 years of age, and it can cause large school- and childcare-associated outbreaks.3 Because clinical guidelines for determining susceptibility of Shigella to azithromycin do not exist, DSA-Shigella isolates are difficult to identify and treatment decisions must be made without azithromycin susceptibility data. | We identified DSA-Shigella isolates through the National Antimicrobial Resistance Monitoring System (NARMS), which in 2011 began measuring azithromycin minimum inhibitory concentrations among all Shigella isolates submitted from public health laboratories to Centers for Disease Control and Prevention for routine surveillance and outbreak evaluation (∼5% of US Shigella isolates). Additional DSA-Shigella isolates were identified through NARMS retrospective studies.1 We defined DSA as azithromycin minimum inhibitory concentration >16 μg/mL using broth microdilution.1 Macrolide resistance genes mphA and ermB were detected using polymerase chain reaction.

Bacteria of the genus Shigella cause approximately 500,000 illnesses each year in the United States. Diarrhea (sometimes bloody), fever, and stomach cramps typically start 1-2 days after exposure and usually resolve in 5-7 days. For patients with severe disease, bloody diarrhea, or compromised immune systems, antibiotic treatment is recommended, but resistance to traditional first-line antibiotics (e.g., ampicillin and trimethoprim-sulfamethoxazole) is common. For multidrugresistant cases, azithromycin, the most frequently prescribed antibiotic in the United States, is recommended for both children and adults. However, not all Shigellae are susceptible to azithromycin. Nonsusceptible isolates exist but are not usually identified because there are no clinical laboratory guidelines for azithromycin susceptibility testing. However, to monitor susceptibility of Shigellae in the United States, CDC's National Antimicrobial Resistance Monitoring System (NARMS) has, since 2011, routinely measured the azithromycin minimum inhibitory concentration (MIC) for every 20th Shigella isolate submitted from public health laboratories to CDC, as well as outbreak-associated isolates. All known U.S. Shigella isolates with decreased susceptibility to azithromycin (DSA-Shigella), and the illnesses caused by them, are described in this report.

To enhance the timeliness of medical evaluation for cholera-like illness during the 2011 cholera outbreak in Hispaniola, printed Travel Health Alert Notices (T-HANs) were distributed to travelers from Haiti to the United States. Evaluation of the T-HANs' influence on travelers' health care-seeking behavior suggested T-HANs might positively influence health care-seeking behavior.

Cholera is rare in the United States (annual average 6 cases). Since epidemic cholera began in Hispaniola in 2010, a total of 23 cholera cases caused by toxigenic Vibrio cholerae O1 have been confirmed in the United States. Twenty-two case-patients reported travel to Hispaniola and 1 reported consumption of seafood from Haiti.